Work of others has been repeated and extended that carnitine levels in various rat tissues is significantly increased in choline fed rats consuming a diet low in methionine. Choline is not participating per se in carnitine synthesis in this situation, but rather may be concerned in carnitine transport. Experiments to support this view will be sought and include (a) determining the distribution of long chain fatty acyl carnitive vs free carnitine in tissues from rats on low methyl diets with or without choline supplementation, (b) (3H) carnitine uptake following liver perfusion in such experimental animals, and (c) a consideration of the possibility of a phosphatide exchange between lecithin and carnitine. Biosynthesis and characterization of "lysine-lipid forms" accumulating in the tissues of rats on low lipotropic diets administered radioactive lysine will be undertaken. A series of carnitine binding proteins have been postulated to exist and to function in the transport of carnitine from its site of synthesis to its site of action. The liver carnitine binding protein (LCBP), the red cell carnitine binding protein (RCBP), the cardiac carnitine binding protein (CCBP) and the muscle carnitine binding protein have been identified. The proteins are distinct from other proteins which are known to bind carnitine as a substrate (carnitine acetyltransferase, carnitine palminoyltransferase and carnitine acylcarnitine translocase). Experiments are in progress to purify, characterize and determine the mechanism of action for each of these carnitine binding.